BioMedical Admissions Test (BMAT) Practice Test 2026 - Free BMAT Practice Questions and Study Guide

As you move down the Group 1 elements, which include the alkali metals such as lithium, sodium, potassium, rubidium, cesium, and francium, the density tends to increase. This occurs because, although the atomic mass of these elements increases significantly as you progress down the group, the volume also increases due to the larger atomic size and the greater number of electron shells. However, the effects of increasing atomic mass generally outweigh the increase in volume, leading to a net increase in density.

For example, lithium has a lower density than sodium, which in turn is less dense than potassium. Each successive element has a greater atomic number and mass, ultimately resulting in an upward trend in density as you go from lithium to francium. The relationship is influenced by the structure and arrangement of atoms within these metals and how their atomic characteristics change down the group.

Understanding this trend helps in predicting the properties of alkali metals, particularly their behavior and usage in various applications within chemistry and materials science. Thus, recognizing the increasing density is crucial in both practical and theoretical contexts when studying these elements.